Miniaturized electronic watch

ABSTRACT

A miniaturized electronic watch in which a tuning fork resonator is sustained in vibration by a transistorized drive circuit energized by a single power cell, the vibratory action being converted into rotary motion to operate a dial train which turns the hands of the watch. The watch movement includes a pillar plate below which the power cell is so positioned that its periphery coincides at one point with the border of the plate, the body of the cell extending to or beyond the geometrical axis of the hands, which axis is normal to the plate. The tuning fork is disposed to one side of the cell below the plate, whereas the dial train is mounted above the cell to provide a highly compact layout.

United States Patent [72] Inventors Werner R. Baumgartner [56]References Cited UNITED STATES PATENTS gjl zg fi 2,900,786 8/1959 Hetzel58/23 [2]] pp No 2,819 3,l 84,910 5/1965 Laviolette 58/28 3,469 3899/1969 Nakai et al 58/23 [22] Filed Jan. 14, 1970 [45] Patented Dec. 21,1971 Primary Examiner-Richard B. Wilkinson [73] Assignee Bulova WatchCompany Inc. Assistant ExaminerEdith C. Simmons New York, N.Y.Attorney-Michael Ebert [32] Priority Feb. 6, 1969 [3 3] Switzerland [31]1798/69 ABSTRACT: A miniaturized electronic watch in which a tuning forkresonator is sustained in vibration by a transistorized v drive circuitenergized by a single power cell, the vibratory acl5MINIATURIZEDELECTRONIC WATCH tion being converted into rotary motion tooperate a dial train 5 Claims, 3 Drawing Fig which turns the hands ofthe watch. The watch movement in- 52 U.S.Cl 58/23 BA cludes a Platewhich the Power is 5 8 /23 tioned that its periphery coincides at onepoint with the border [51] GMc 3/00 of the plate, the body of the cellextending to or beyond the [50] 58/23 50 geometrical axis of the hands,which axis is normal to the 6 plate. The tuning fork is disposed to oneside ofthe cell below the plate, whereas the dial train is mounted abovethe cell to provide a highly compact layout.

Z5 5 3 WA 32 a9 Ill-H Z2 MM. l7 1 ll l) 178 ll Ill 4i i p \T Z4- 57 r" ifarm/c I Zoe g 36 11150184) l 4o L l as PATENTEB UECZI I97! SHEET 1 BF 2INVENTO s This invention'relates generally to battery-operatedelectronic timepieces, and more particularly to a miniaturizedelectronic watch including a tuning fork resonator whose vibrations areconverted into rotary motion for operating dial pointers.

In electronic timepieces of the type disclosed in US. Pat. No.Re.26,322, a battery-energized transistor drive circuit acts to sustainthe vibratory motion of a tuning fork. This motion is transferred by apawl and ratchet mechanism to a rotary movement including a gear trainand dial pointers or hands.

In tuning fork electronic watches of the type heretofore known, thestructural arrangement has been such as to preclude a reduction in thediameter and other dimensions of the watch movement to a degree makingit possible to house the movement within a ladies watch case. Thoughsuch watches have been made in relatively large models having masculineappealyit has not hitherto been feasible to miniaturize the dimensionsto a point rendering the watch acceptable to ladies.

The main obstacle to a further reduction in the dimensions of anelectronic timepiece of the tuning fork type, is the power cell. Thissingle-cell battery, which is round and buttonlike, occupies arelatively large portion of the useful volume of a watch movement. Inthe conventional layout, the power cell is laterally displaced from thedial train, as a consequence of which a watch movement with acommercially available type of power cell has a diameter of at least 25millimeters. This diameter is beyond the limits acceptable inladies-model watches.

SUMMARY or INVENTION In view of the foregoing, it is the main object ofthis invention to provide a miniaturized electronic watch movement whichmay be housed in a relatively small case and is, therefore, acceptablein lades models or for other applications in which small size is adesideratum.

More specifically, it is an object of the invention to provide a layoutfor an electronic watch of the tuning fork type, in which the singlepower cell is disposed below the pillar plate with its peripherycoincident to the border of the plate at at least one point, the forkbeing also disposed below the plate in side-by-side relation to thecell, whereas the dial train for turning the hands is mounted above thecell, to afford a highly compact structure.

A significant feature of the invention is that the layout of the dialtrain, power cell, tuning fork, and the associated electronic assembly,is such as to make possible a movement whose diameter is less than 20millimeters, such dimensions being suitable for ladiesmodels.

Briefly stated, these objects are accomplished in a tuning forkelectronic watch movement in which the single buttonlike power cell forenergizing the electronic drive circuit is placed below the pillar platewith at least one point on its periphery coincident with the border ofthe plate, the body of the cell extending beyond the geometrical centerof the hands. The tuning fork is disposed in side-by-side relationshipto the cell below the plate and is operatively coupled to the dial trainfor turning the hands, which dial train is mounted above the cell.

OUTLI E or DRAWING For a better understanding of the invention, as wellasother objects and further features thereof, reference is made to thefollowing detailed description to be read in conjunction with theaccompanying drawing, wherein:

FIG. 1 is a schematic view of an electronic watch in accordance with theinvention as viewed from the dial side, with the dial, pillar plate, andcase omitted to facilitate an understanding of the invention;

FIG. .2 is a transverse section taken in the plane indicated by line 2-2in FIG. 1; and

FIG. 3 is a schematic diagram of the electronic circuit of the watch.

DETAILED DESCRIPTION OF INVENTION Referring now to the drawing, aminiaturized watch movement in accordance with the invention includes acircular pillar plate 10, above which is mounted a watch dial 11. Themovement fits within a case (not shown). The purpose of the invention isto provide a movement of small diameter adapted to fit within a ladiesmodel case of 20 millimeters or less.

Disposed below pillar plate 10 is a buttonlike, round power cell 12whose flat top and bottom surfaces are parallel to the plane of pillarplate 10. Cell 12 is tangentially disposed with respect to the border ofpillar plate 11, so that point 13 on the circumference of the cell issubstantially in line with the border. Depending on the shape of thepower cell relative to the pillar plate, more than one coincidence pointis possible.

The seconds, minute and hour hands indicated diagrammatically by linesS, M and H, are mounted respectively on arbor 14, cannon 15, and tube16, respectively, which are coaxially arranged. The axis of arbor 14,which is the geometrical axis X of the hands, coincides with the centerof pillar plate 10. The diameter of cell 12 is somewhat greater than theradius of the pillar plate; hence the body of the cell extends wellbeyond the geometrical axis X of the hands. Therefore, in the embodimentillustrated, the axis X passes through the power cell. In otherinstances, thecell may come quite close to the axis, or go only slightlybeyond it.

The electronic watch includes a tuning fork, generally designated bynumeral 17, having two tines 17A and 17B, and a reentrant mounting stem18 which is attached to the underside of the pillar plate by screws 19.The fork is positioned in side-by-side relationship to cell 12, thetines lying in a common plane which is parallel to the top and bottomsurfaces of the cell.

At the free ends of tines 17A and 17B are attached permanent magnets 20Aand 208 which cooperate with a stationary pancake-shaped coil 21 havingsensing and drive windings 21A and 218 (FIG. 3), the magnetic flux inthe airgap of the magnets being perpendicular to the plane of the coil.Coil 21 is supported from a projection 22 formed on a plastic module 23which houses the electronic assembly, generally designated by numeral24.

This assembly, as best seen in FIG. 3, is constituted by a transistor Tand a resistance capacitance network RC which is associated with thesensing and drive windings 21A and 218. The manner in which the circuitacts to sustain the tuning fork in vibration is explained in US. Pat.No. 2,971,323, and will, therefore, not be repeated herein.

It will be seen that the outer side of module 23 is convex to conform tothe corresponding curvature of the border of the pillar plate on whichit is mounted, whereas the inner side is concave to conform to thecurvature of cell 12, while the profile of the upper side follows thatof the tuning fork. Thus the shape of module 23 permits optimum use ofthe space between the fork, the cell, and the periphery of the movement.

An index finger 25 is attached to tine 17A, the finger 25 having ajewelled tip which engages the teeth of an index wheel 26. A pawl (notshown) cooperates with the wheel to prevent retrograde motion thereof.The pinion 27 of index wheel 26 meshes with the teeth of a wheel 28whose pinion 29 drives a wheel 30. The pinion 31 of wheel 30 drives anintermediate wheel 32, which in turn drives a pinion 33 mounted on thelower end of the arbor 14 for turning the seconds hand S.

On the arbor 35 of intermediate wheel 32, is attached a pinion 34 whichdrives wheel 36.- A friction clutch (not shown) is interposed betweenwheel 36 and cannon 15. Cannon 15 is provided with a pinion 37 whichmeshes with minute wheel 38, which, by means of pinion 39, drives hourwheel 40 mounted on tube 16.

It will be seen that all dial train elements supporting hands S, M andH, are disposed above power cell 12. As seen from the backside of themovement, all of these parts, including minute wheel 38, are hidden bycell 12. Thus ,the cell, instead of being laterally displaced from thedial train elements, as in the conventional electronic watcharrangement, are disposed thereover, making possible a substantialreduction in the diameter of the movement.

While there has been shown a preferred embodiment of a miniaturizedelectronic watch in accordance with the invention, it will beappreciated that changes and modifications may be made within the scopeof the invention For example, other parts of the wheel train may beplaced on top of the cell in addition to those shown. This depends onthe shape of the resonator, which is not limited to the tuning forkshown, and on the arrangement of the other electronic and mechanicalcomponents.

What we claim is:

l. A miniaturized electronic timepiece comprising:

A. a pillar plate having a dial thereover;

B. timing hands turnable on said dial with respect to a geometrical axispassing through the center of said plate,

C. a button-shaped, single power cell disposed below said plate at aposition in which one point on the periphery of said cell substantiallycoincides with the border of said plate, the body of the cell extendingat least to said axis, the flat top surface of said cell being parallelto said plate, D. a mechanical resonator serving as a frequencystandard, said resonator being constituted by a tuning fork sustained invibration by an electronic drive circuit energized by said cell, thefork being disposed below said plate to one side of said cell and havinga pair of tines which lie in a plane parallel to the top and bottomsurfaces of said cell, and

E. means to convert the vibrations of said resonator to rotary motionfor turning said hands, said means including a dial train operativelycoupled to said hands and disposed above the plane defined by the topsurface of said cell.

2. A timepiece as set forth in claim 1, wherein said timing hands areconstituted by seconds, minute and hour hands, the seconds hand beingsupported on an arbor lying along said geometrical axis, the minute handbeing supported on a cannon coaxially disposed with respect to saidarbor, said hour hand being supported on a tube concentric with saidcannon, said arbor being operated by a pinion attached to the endthereof, which pinion is hidden by the cell when looking at the movementfrom the side opposing the dial.

3. A timepiece as set forth in claim 2, wherein said cannon and tube arealso hidden by the cell.

4. A timepiece as set forth in claim 3, wherein said cannon is engagedby a minute wheel which is disposed above the plane defined by the topsurface of said cell and is hidden by said cell when the movement isviewed from the side opposing the dial.

5. A timepiece as set forth in claim 3, wherein the com ponents formingsaid electronic drive circuit are contained in a plastic module disposedbetween the border of said plate, the periphery of the cell, and onetine of the fork, the outer side of the module being curved to conformto the curvature of said border, the inner side of the module beingcurved to conform to the curvature of said cell.

1. A miniaturized electronic timepiece comprising: A. a pillar platehaving a dial thereover; B. timing hands turnable on said dial withrespect to a geometrical axis passing through the center of said plate,C. a button-shaped, single power cell disposed below said plate at aposition in which one point on the periphery of said cell substantiallycoincides with the border of said plate, the body of the cell extendingat least to said axis, the flat top surface of said cell being parallelto said plate, D. a mechanical resonator serving as a frequencystandard, said resonator being constituted by a tuning fork sustained invibration by an electronic drive circuit energized by said cell, thefork being disposed below said plate to one side of said cell and havinga pair of tines which lie in a plane parallel to the top and bottomsurfaces of said cell, and E. means to convert the vibrations of saidresonator to rotary motion for turning said hands, said means includinga dial train operatively coupled to said hands and disposed above theplane defined by the top surface of said cell.
 2. A timepiece as setforth in claim 1, wherein said timing hands are constituted by seconds,minute and hour hands, the seconds hand being supported on an arborlying along said geometrical axis, the minute hand being supported on acannon coaxially disposed with respect to said arbor, said hour handbeing supported on a tube concentric with said cannon, said arbor beingoperated by a pinion attached to the end thereof, which pinion is hiddenby the cell when looking at the movement from the side opposing thedial.
 3. A timepiece as set forth in claim 2, wherein said cannon andtube are also hidden by the cell.
 4. A timepiece as set forth in claim3, wherein said cannon is engaged by a minute wheel which is disposedabove the plane defined by the top surface of said cell and is hidDen bysaid cell when the movement is viewed from the side opposing the dial.5. A timepiece as set forth in claim 3, wherein the components formingsaid electronic drive circuit are contained in a plastic module disposedbetween the border of said plate, the periphery of the cell, and onetine of the fork, the outer side of the module being curved to conformto the curvature of said border, the inner side of the module beingcurved to conform to the curvature of said cell.